This invention relates generally to a one directional flow valve assemblies for fluid systems and particularly to assemblies which more efficiently permit the ambient environment to equalize negative pressure differentials within the fluid system while preventing positive pressure gases from escaping into the ambient environment. The present invention particularly provides improved and efficient airflow characteristics which are for air admittance valve assemblies. These valve assemblies are constructed and arranged to provide an automatic one-way valve structure operative in low pressure differential environments such as in the drain portion of a plumbing system. The valve assemblies of the invention provide responsive and sensitive air inlet valve structures for, but not restricted to, indoor use environments to vent into plumbing systems.
Air admittance valve assemblies are disclosed in Applicant's U.S. Pat. No. 6,415,816 ('816 Patent) and which is incorporated by reference herein. The air admittance valve assemblies disclosed in the '816 Patent utilize tension membranes in cooperation with a singular circular valve seat. The present invention provides new body member structures over those of the '816 Patent which more efficiently permits air inflow, air through flow and air outflow. The valve body member of the invention provides novel inlet and outlet ports and provides a cooperating air deflection member mounted circumferentially about the tension membrane or other sealing member to deflect the airflow moving through the valve approximately 180°, thereby providing a reaction force to completely open the valve at low airflow rates.
The air admittance valve assembly of the present invention provides a valve body structure which improves intake airflow by providing a plurality of radially disposed inlet ports or chutes. The inlet chutes communicate with a centrally disposed valve chamber and are disposed in the valve body to define a plurality of peripherally positioned and circumferentially arranged air outlet chutes. The sealing membrane carrier structure is provided with a peripheral air deflection or wing member which results in the radial movement of airflow from the valve chamber down and through the outlet chute(s).
The improved valve body configuration of the present invention significantly increases airflow rate by decreasing airflow resistance and providing increased inflow and outflow areas. Firstly, the circumferential airflow component of velocity is minimized by the novel body design. Secondly, directed inflow patterns are provided by upwardly angled inlet ports. Thirdly, an air deflector shield is placed around the sealing membrane providing increased seal opening at each flow rate of air compared to structures not incorporating an air deflector shield.
The first feature of reducing the circumferential airflow component reduces the Coanda effect of the air flowing across the bottom of the sealing membrane. This reduces the suction on the bottom of the sealing membrane permitting increased seal openings at any differential pressure. The second feature of upwardly angled inlet ports reduces the amount of angular deflection that the air stream must undergo. This reduces the pressure drop at any given airflow rate. The third feature of an air deflection shield generates a reaction force from the near 180 degree turn that the air stream makes when impinging upon the sealing member. This reaction force assists in opening the valve. Air admittance valves incorporating these three new features exhibit dramatically improved air flow rates for any given sized device without any compromise to sealing.
It is the advantage of the present invention providing an automatic air admittance valve which effectively and reliably allows ambient make up air under ambient pressure to enter and equalize a negative pressure differential in a plumbing drain and waste system while preventing the discharge of contaminated and undesirable gasses under zero or positive pressure conditions. It is further the object of the present invention to provide a flexible sealing diaphragm for a gravity controlled low pressure air admittance valve assembly which is reliable and effective for venting into such plumbing systems. It is still a further object of the invention to provide a valve body structure which efficiently moves and directs air into, through and out of the valve body.